"We have made our preparations, we have finalized our operation plans, given the necessary instructions," Erdogan told his ruling party members in Ankara.
Turkey has been "forced" to take military action for its own security and so that Syrians displaced by the war can return home as soon as possible, Erdogan said.
Turkey says it hosts 3.6 million Syrian refugees.
Erdogan previously said Ankara planned to relocate as many as 2 million Syrians to a 30-kilometre-deep safe zone that would stretch from the east of the Euphrates to the border with Iraq.
Turkey already controls areas west of the Euphrates following two military operations there.
NATO allies Turkey and the US have been carrying out joint air and ground patrols along the north-eastern Syrian border with Turkey since the two agreed in August to create a "safe zone" there.
Turkey considers the US-backed Kurdish People's Protection Units (YPG) in the region as terrorists and has called for it and other allegedly linked groups, including the Syrian Defence Forces (SDF), to be completely removed from its borders.
Washington relied on both the YPG and the SDF in their attempt to defeat the Islamic State extremist group in Syria.
The US has been carrying out joint military operations against the Islamic State in Iraq and Syria under the name Operation Inherent Resolve (OIR).
"Air and ground patrols demonstrate our continued commitment to address Turkey's legitimate security concerns," OIR spokesman Myles B Caggins tweeted, reiterating its cooperation with the SDF "on crushing [Islamic State] remnants."
Turkey and the US conducted seven joint air and three ground patrols in eastern Syria as part of safe zone plans, the US European Command separately tweeted.
Erdogan has repeatedly warned that if the zone is not established by the end of September, then Turkey will have to implement its own military plans.
It was never clear who would control the zone and how.
The SDF "will not hesitate to prevent any provocative attack by Turkey into an all-out war on the entire border in order to defend ourselves and our people," SDF spokesman Mustafa Bali tweeted Saturday.
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